The threat of an intentional release of bacterial select agents prompts the need for their rapid, culture-free diagnosis that can be conducted in the field or in laboratories with only basic diagnostic capabilities. Optical fiber biosensors are attractive devices that can detect, record, and transmit information regarding a physiological change or the presence of various biological and chemical materials in the environment. These devices can be easily operated by non-specialist personnel and do not require high vacuum, high temperature, organic solvents, or clean-room facilities. Our overall goal is to develop a highly sensitive, portable, detection device that will serve as a platform technology for a menu of medically relevant and clinically relevant disease targets, including infectious disease agents. For this project, we will develop sensitive, specific, and rapid nanoscale optical fiber biosensors for the diagnosis of the Category A and B select agents Francisella tularensis, Burkholderia mallei, and B. pseudomallei, as proof of principal that this technology can be applicable to a wide variety of other agents and biological markers. Our hypothesis is that specific antigenic epitopes or regions of the DNA of these bacteria can be detected under field or in a basic laboratory setting with these optical biosensors to enable the diagnosis of these or other bacteria. To accomplish our goal our specific aims are to: (i) develop a DNA-hybridization assay using nanoscale optical fiber biosensors coupled to DNA probes to detect specific oligonucleotide sequences;(ii) develop an antigen-binding assay using nanoscale optical fiber biosensors coupled to antibodies to detect specific antigens;and (iii) enhance the sensitivity and optimize the specificity of the nanoscale optical fiber biosensors for detecting oligonucleotide sequences and antigens specific to infectious bacteria. In addition, we will use Real-Time PCR and latex agglutination assays as control assays to compare the sensitivity and specificity of DNA-based or antigen- based optical fiber biosensor assays. The novel bioengineered optical fiber assay is rugged, portable, and inexpensive when compared to competing technologies such as surface plasmon resonance. These sensors will fill an important void that exists in the rapid, culture-free diagnosis of infectious agents, particularly in regions where simple and portable devices are mostly needed. PUBLIC HEALTH RELEVANCE: We propose to develop sensitive, specific, and rapid nanoscale optical fiber biosensor for the diagnosis of the Category A and B select agents Francisella tularensis, Burkholderia mallei, and B. pseudomallei. The novel bioengineered optical fiber assay is rugged, portable, and inexpensive when compared to competing technologies such as surface plasmon resonance. These sensors will fill an important void that exists in the rapid diagnosis of Category A and B select agents, but can be broadly applicable. Therefore, these assays will act as proof-of principle for their application to the diagnosis of a variety of biological agents.